Dictionary of Ichthyology  

illicium (plural illicia) = a long, flexible spine on the dorsal median surface of the head usually with a modified tip or esca. Believed to be modified spine from the first dorsal fin and retractable in some species. Acts to lure prey close enough to be captured. Found in Lophiiformes.

Corynolophus reinhardti (= Himantolophus groenlandicus), from Jordan's "A Guide to the Study of Fishes", 1905. Photograph by Brian W. Coad.

Canadian Museum of Nature